ZF5 4x4 Extension Housing Cracked?!?! Project Brutus, Ep. 10

I'm in the process of rebuilding a ZF5 S47 4x4 transmission for Project Brutus, and the extension housing is cracked.  I took it to be TIG welded, and now it has another crack!  I could use some input on what I should do next.  Thanks!

PS - I almost forgot - this is the second busted ZF5 extension housing we've had on Brutus -- as you saw in Episode 2, the original 2WD ZF5 transmission had a broken mount on the extension housing!